The main outcome in policy making has been acknowledged in the Basque province of Guipuzcoa, where this report has been influential on the provincial president who reintroduced measures to limit impact of the provincial Wealth Tax. Similarly, the president of Extremadura had to reduce the inheritance tax as the Index revealed that neighboring regions had much lower rates negatively impacting Extremadura’s tax competitiveness. Finally, other politicians, in areas ranging from the Canary Islands to Navarre, have also used the Index in their media statements, regional parliament speeches or in debates with their opponents.